Grinding-wheel.



F. B. JACOBS.

GRINDING WHEEL.

APPLIcATIoN FILED :um: za, 1913.

Patented Mar. 10, 1914.

Il l A Tron/vans'.

FREDERIC B. JACOBS. 0F INDIANAPOLIS, INDIANA.

GRINDING-WHEEL.

Specification of Letters Patent.

Patented Mar. 10, 1914.

Application mea .Tune as, 1913. serial No. 775,381.

i To all whom t may concern Indianapolis, in the county of Marion and,

State of Indiana, have invented certain new and usefuly Improvements in Grinding- Wheels, of which the following is a speciication.

This invention relates to grinding wheels which are molded out of suitable material for that purpose, which material may be made up of coarse or fine grained material in order to produce grinding wheels for the character of work to be performed. For instance, a grinding wheel to be run at a peripheral speed of five thousand feet per minute will not be made of a degree of hardness that is required in'a wheel running at a more reduced rate of speed. With these conditions existing incident to the manufacture of grinding wheels it at once becomes'ap'parent that as the diameter of a wheel of a prescribed degree of hardness yis reduced in diameter through the action of abrasion, its peripheral speed per minute is correspondingly reduced so that the wearing down of the wheel is materially increased by the ac- 4tion of abrasion. At the present time, there are no grinding wheels manufactured wherein the density of the material forming said wheels gradually increases from their peripheries to their axes.

The object of my invention is to provide a grinding Wheel of the above character whichI will be formed at its outer peripheral edge to a degree of hardness corresponding to the peripheral speed to be initially imparted to the wheel, so that the texture of said wheel will be more dense toward its axis, the increase in density compensating for the reduction in its peripheral travel incident to its decrease in diameter through the action of abrasion, so that a grinding wheel of proper peripheraldensity is at all times presented to the object worked upon.

` I accomplish the above object of the invention by certain means illustrated in the accompanying drawing, forming a part hereof, in which- Figure 1 is a cross section of the grinding wheel as initially formed within the pressbox, showing the adjacent faces of the pressbox cut on inclined planes which intersect beyond the periphery of the wheel. Fig. 2 is a transverse sectional view through the press-box to which the wheel-blank has been transferred, said adjacent faces being shown as arranged in parallel planes. Fig. 3 shows the shape of the wheel in cross section after the same has been compressed into a merchantable product.

Referring to the drawings, 10 represents the bottom of the press-box, 11 the side members thereof, and 12 the top member which is susceptible of vertical movement between the side members 11, so that the material from which the grinding wheel is formedy may be compressed. Arranged cen trally within the press-box is a pin l5 which forms a centrally located aperture within the finished wheel to enable the latter to be mounted upon a suitable shaft when in use.

17 represents the grinding wheel proper which is formed out of suitable material of abrasive character, to produce a wheel for the work desired, in which the material is held together by a suitable binder, old and well-known in the art of manufacturing grinding wheels. Up to this stage in the operation of manufacturing grinding wheels, as illustrated in Fig. l and in which the upper member 12 has reached the limit of its movement, and wherein a uniform pressure has been applied to the material forming the grinding wheel, a wheel is produced with a uniform degree of hardness from its periphery to its axis. After this initial operation of forming the wheel, as shown in Fig. 1 of the drawings, the wheel-blank is transferred to another press-box in which the adjacent faces of the bottom member 10 and the u per member 12 are arranged in parallel p anes. The position the wheelblank occupies between said members 10 and 12 and before pressure is applied to said wheel-blank, is clearly illustrated in Fig. 2 of the drawings. When pressure is applied to the member 12 a re-adjustment of the material forming the wheel-blank takes place. the 'material near the axis being compressed more firmly than elsewhere, the amount of pressure applied to the wheel-blank gradually decreasing toward the periphery of the Wheel, so that the density of the material forming said wheel is gradually reduced from the axis to the periphery of the wheelblank.

The amount of inclination initially imparted to the wheel-blank governs the distribution of pressure against the wheelblank, so that the degree of hardness imparted to the wheel-blank under given pressure is also controlled. The greater the degree lv of inclination imparted to the adjacent faces of the members 10 and 12, wherein a similar degree of inclination is initially imparted to the Wheel-blank, results in the production of a correspondingly denser and harder grinding Wheel When the latter undergoes to its axis, said increasing degree of hardness compensating for the decrease in the diameterof the Wheel through abrasion, so

lthat a grinding Wheel is finally produced which will-at allr times present to the object worked upon a surface of the desired degree of hardness until such time that the diameter of the Wheel has been reduced to unfit it for further service.

Having thus fully described my said invention, what I desire to secure by Letters Patent, is-

1. As an article of manufacture, a grinding Wheel of gradually increasing density from its periphery toward its center.

2. As a new' article of manufacture, a grinding Wheel of varying compactness, said compactness being the same .at all equal radial distances from the axis of the Wheel. f 3. As a new article of manufacture, a grinding Wheel composed of granular material, said material Varying radially and uniformly in compactness.

In witness whereof, I have hereunto set my hand and seal at Indianapolis, Indiana, this 7 th day of June, A. D. one thousand nine hundred and thirteen.

FREDERIC B. JACOBSa [L. s.]

Witnesses:

B. OVERMAN, F. W. WOERNER, 

